1. Field of the Invention
The present invention relates to an alarm device and, more particularly, to an alarm device for a bicycle.
2. Description of the Related Art
A first conventional lock includes a cable extended through the tire and the spokes of a bicycle so as to lock the bicycle. However, the burglar can directly carry away the whole bicycle so that the first conventional lock fails to achieve a burglarproof purpose efficiently. A second conventional lock comprises an elastic and flexible metallic chain whose one end is extended through the frame of the bicycle and an object, such as an electric pole, a fence, a bar and the like, and is locked onto the other end of the metallic chain. Thus, the bicycle is limited to the object to achieve a burglarproof purpose. However, the second conventional lock cannot transmit an audible alarm signal to the rider when a thief is breaking the metallic chain, thereby decreasing the anti-theft effect.